1. Mutations
TSW identify and describe the various types of mutations and their effects

2. Gene Mutations Produce changes in a SINGLE gene
Point Mutation: involve changes in one or a few nucleotides
a single point in a DNA sequence

3. Substitutions 1 base is changed to another
Usually affects no more than 1 amino acid
Example:
T A C G C A T G G A A T
T A C G T A T G G A A T

4. Insertions 1 base is inserted into a DNA sequence
Usually has more dramatic effects
Example:
T A C G C A T G G A A T
T A T C G C A T G G A A T

5. Deletions 1 base is removed from a DNA sequence
Usually has more dramatic effects
Example:
T A C G C A T G G A A T
T _ C G C A T G G A A T
T C G C A T G G A A T

6. Frameshift Mutations Shift the “reading frame” of a genetic message
May change every amino acid that follows the mutation
May make a protein unable to perform its original function

7. Chromosomal Mutations
Involve changes in the # & structure of chromosomes
May change the location of genes on a chromosome
May change the # of copies of some genes

9. 1. Deletions
Lose ALL or part of a chromosome

10. 2. Duplications
Produce extra copies part of a chromosome

11. 3. Inversions
Reverse the directions of parts of a chromosome

12. 4. Translocation
One part of a chromosome breaks off & attaches to another

13. Significance of Mutations
Most are neutral (have little or no effect on gene expression or protein function)
Some are harmful (cause genetic disorders & cancer) or even lethal
Some are beneficial (source of genetic variation)

14. Polyploidy Beneficial mutation Extra set of chromosomes (3N or 4N)
Often larger & stronger than 2N